Maciej,
Thanks a lot, again.
I've put the extracted files and repertories on a server.
With the one I play with Guvnor 5.5 - jBPM 5.4, I succeed in displaying the content of such service repository and importing the FTP item (for other items the internal structure is missing a .wid file).
After some work about declaration in package assets, I had it displayed in the shape repository panel under service tasks and added it in a BPMN2 process. :)
Now I Will look at work item handler interface definition.
Kind regards,
David.